Reactions confirming the qualitative composition of sulfuric acid. Properties of non-metals and their compounds

Practical work No. 4
Experimental tasks on the topic “Oxygen subgroup”

Problem 1

Carry out reactions to confirm the qualitative composition of sulfuric acid. Write the reaction equations.

Problem 2

Place 1-2 zinc granules in a test tube and pour about 1 ml of dilute sulfuric acid into it. What are you observing? Write the reaction equation and consider redox processes.

Problem 3

Pour 1-2 ml of sodium sulfide solution into two test tubes. Pour the same volume of chlorine water into one of them, and bromine water into the other. What are you observing? Explain your observations. Write the equations for the corresponding reactions in molecular and ionic form.

Problem 4

You are given three test tubes with solutions. Determine which one contains hydrochloric acid, sulfuric acid and sodium hydroxide. Write the equations for the corresponding reactions in molecular and ionic form.

Problem 5

Determine whether table salt contains sulfates. Write the reaction equations in molecular and ionic form.

Problem 6

Using characteristic reactions, determine whether the salt given to you is sulfate, iodide or chloride. Write the equations for the corresponding reactions in molecular and ionic form.

Problem 7

Starting from copper (II) oxide, obtain a solution of copper (II) sulfate and isolate crystalline copper sulfate from it. Write the equations for the corresponding reactions in molecular and ionic form.

Problem 8

You are given three test tubes with solutions of sodium sulfate, sulfite and sodium sulfide. Using only one reagent, determine which test tube contains each substance. Write the equations for the corresponding reactions in molecular and ionic form.

Practical work No. 5
Experimental tasks on the topic “Subgroups of nitrogen and carbon”

Problem 1

Carry out reactions that can be used to prove that the substance given to you in closed containers is:

a) ammonium chloride;
b) sodium carbonate;
c) ammonium nitrate;
d) ammonia;
e) calcium carbonate;
e) sodium silicate.

Problem 2

Prove experimentally that ammonium sulfate and ammonium nitrate cannot be mixed with lime before applying these fertilizers to the soil, and explain why. Write the reaction equations.

Problem 3

Prove experimentally that:

Write the equations for the reactions carried out in molecular and ionic form.

Problem 4

Obtain ammonia from the following salts:

a) ammonium chloride;
b) ammonium sulfate;
c) ammonium nitrate.

Write the equations for the reactions carried out in molecular and ionic form.

Problem 5

Carry out the reactions that are expressed by abbreviated ionic equations:

Write the equations for the reactions carried out in molecular and ionic form.

In four test tubes you are given crystalline substances: sodium sulfate, zinc chloride, potassium carbonate, sodium silicate. Determine which test tube contains each substance. Write reaction equations in molecular and ionic form.

Practical work No. 6
Receiving, collecting and recognizing gases

Option 1

Experience 1.
Production, collection and recognition of hydrogen

Assemble the device for obtaining gases and check it for leaks. Place 1-2 zinc granules in a test tube and pour 1-2 ml of hydrochloric acid into it. Close the test tube with a stopper with a gas outlet tube (see Fig. 76) and place another test tube on the tip of the tube. Wait a while for the test tube to fill with the released gas.

Remove the test tube from the gas outlet tube and, without turning it over, slightly tilt it, bring it with the hole to the burning alcohol lamp. If there is pure hydrogen in the test tube, then a dull pop will be heard, if there is a “barking” sound, hydrogen is collected in a mixture with air, i.e., “explosive gas” is collected in the test tube.

Questions and tasks:

1. What happens when zinc reacts with hydrochloric acid? Create an equation for the reaction and characterize it using all the studied characteristics of the classification of chemical reactions.
2. Describe the physical properties of hydrogen directly observed during the experiment.
3. Describe how hydrogen can be recognized.

Experience 2.
Production, collection and recognition of ammonia

Assemble the device as shown in Figure 168 and check for leaks.

Rice. 168.
Production of ammonia and its collection by air displacement method

Pour one spoonful of ammonium chloride and calcium hydroxide into a porcelain cup to burn the substances. Stir the mixture with a glass rod and pour into a dry test tube. Close it with a stopper and secure it in the tripod leg (pay attention to the tilt of the test tube relative to the hole!). Place a dry ammonia collection tube on the gas outlet tube.

First, heat the entire test tube with a mixture of ammonium chloride and calcium hydroxide with 2-3 movements of the flame, and then heat only in the place where the mixture is located.

To detect ammonia, bring wet phenolphthalein paper to the hole of the test tube turned upside down.

Stop heating the mixture. Remove the test tube in which the ammonia is collected from the gas outlet tube. Immediately cover the end of the gas outlet tube with a piece of wet cotton wool.

Immediately close the opening of the removed test tube with your thumb, immerse the test tube with the hole down in a container of water and release the hole of the test tube. What are you observing? Why did the water in the test tube rise? Close the hole of the test tube under water with your finger and remove it from the vessel. Invert the test tube and add 2-3 drops of phenolphthalein solution. What are you observing?

Carry out a similar reaction between solutions of alkali and ammonium salt when heated. Apply wet indicator paper to the opening of the test tube. What are you observing?

Questions and tasks:

1. What happens when ammonium chloride and calcium hydroxide react? Create an equation for the reaction and characterize it using all the studied characteristics of the classification of chemical reactions.
2. Describe the physical properties of ammonia that are directly observed experimentally.
3. Describe at least two ways to recognize ammonia.

Option 2

Experience 1.
Obtaining, collecting and recognizing oxygen

Assemble the device as shown in Figure 109 and check for leaks. Fill the test tube approximately 1/4 of the volume with potassium permanganate KMnO4, place a loose ball of cotton wool at the opening of the test tube. Close the test tube with a stopper with a gas outlet tube. Secure the test tube in the stand leg so that the end of the gas outlet tube reaches almost to the bottom of the oxygen collection vessel.

First, heat the entire test tube with KMnO4 with 2-3 movements of the flame, and then heat only in the place where the substance is located.

Check the presence of oxygen in the vessel with a smoldering splinter.

Questions and tasks:

1. What happens when potassium permanganate is heated? Create an equation for the reaction and characterize it using all the studied characteristics of the classification of chemical reactions.
2. Consider the recorded reaction in terms of oxidation-reduction processes.
3. Describe the physical properties of oxygen that are directly observed in experiment.
4. Describe how you recognized oxygen.

Experience 2.
Production, collection and recognition of carbon monoxide (IV)

Place several pieces of chalk or marble in a test tube and add 1-2 ml of dilute hydrochloric acid. Quickly close the tube with a stopper and a gas outlet tube. Place the end of the tube into another test tube with 2-3 ml of lime water.

Watch for a few minutes as gas bubbles pass through the lime water.

Questions and tasks:

1. What happens when chalk or marble reacts with hydrochloric acid? Create an equation for the reaction and characterize it using all the studied characteristics of the classification of chemical reactions.
2. Consider the reaction performed in the light of the theory of electrolytic dissociation.
3. Describe the physical properties of carbon(IV) monoxide that are directly observed experimentally.
4. Describe how you recognized carbon (IV) monoxide.

Sections: Chemistry

Lesson format: practical work.

Lesson objectives:

• Educational:

Repeat and consolidate practical skills in performing chemical experiments, handling reagents, and observing safety regulations;
- learn to select the reagents necessary for work, assume observed phenomena, and draw conclusions;
- consolidate skills in drawing up equations of ion exchange reactions, drawing up dissociation equations, full and abbreviated ionic equations.

• Developmental:
continue to develop self-education skills - work with teaching aids and additional literature.

• Educational:

Continue the formation of ideological concepts about the knowability of nature, the cause-and-effect relationship between the composition, structure and properties of substances;
- students must be able to work carefully and consciously follow established rules (for example, safety precautions).

Equipment: graphic projector with code films, solubility table, TV, programmed teaching aid, tables for filling out a work report and reference tables ( Annex 1), racks with test tubes, trays, waste bottles, hourglasses, indicators - phenolphthalein and litmus, solutions of barium chloride, iron (II) sulfate, sodium carbonate, sulfuric acid, silver nitrate, red blood salt, sodium hydroxide, calcium chloride, copper (II) sulfate, calcium hydroxide, hydrochloric acid. To solve problems of recognizing substances, students are given solutions of sulfuric acid, calcium hydroxide and calcium chloride in numbered bottles.

Lesson structure:

• Organizing time. 1 min.
• Motivation. 1 min.
• Repetition of methods for determining cations and anions in solutions. 2 minutes.
• A message about the procedure for performing experiments and evaluating the work. 2 minutes.
• A reminder about the structure of the programmed teaching aid. 1 min.
• Completing tasks using a programmed teaching aid. 35 min.
• Summarizing. 3 min.

During the classes

Motivation. An entire science, analytical chemistry, is engaged in recognizing substances and proving their composition. It employs more people than chemical production.

Repetition. Let's remember the methods for determining cations and anions in solutions (you can use the provided reference materials):

• flame coloring (the only way to detect sodium). The teacher shows a fragment of a video film;
• precipitation reactions (little and insoluble substances are formed - white or colored precipitates);
• color reactions - usually a change in the color of indicators in acidic and alkaline solutions;
• reactions that release gases, such as carbon dioxide. The teacher conducts demonstration experiments.

Sequence of work execution.

You have to complete 4 experiments on your own. Each of the first three takes 7 minutes. If the time required is greater, the third experiment may not be performed. Use an hourglass to control time. At the end of the lesson, you give the teacher the answer to the substance recognition task (experiment 4) in the form of two completed tables. At the end of the lesson, you receive two grades: for completing the test experiment and for completing all the work.

Sequence of work with programmed guide(Table 1). You read the first task, printed on the left page of the textbook spread at the top, and write down the missing word, formulated answer, reaction equation on this page. On the left side of the right page of the spread, separated by a vertical line, the necessary explanations and drawings are provided to help you arrive at the correct answer. Having completed the task, turn the page and on the right side of the next spread, find the answer and match what you wrote down with the correct one, printed under the same number.

Once you have received confirmation that your answer is correct, you can move on to the next task, which is printed at the top of the left page of the next spread and is numbered one more than the previous one.

Before conducting experiments, read the safety regulations.

Safety regulations:

• Substances should not be touched by hand or tested for taste and smell.
• Do not mix substances you do not know unless instructed by your teacher.
• When performing experiments, use small doses of substances.
• Handle acids and alkalis with care.
• If solutions get on your hands or clothing, wash them off immediately with plenty of water.
• After work, wash your hands with soap.
• Use only clean laboratory glassware.
• Do not empty the remaining substances or pour them back into the container with clean substances.

I have read the safety rules (a) ………………… (signature)

Table 1

Programmed aid

Left page spread of the manual	Right page spread of the manual
Exercise	Explanation of the task	Answer
Experience 1 Confirm the quality composition of barium chloride 1. In an aqueous solution, barium chloride dissociates into ions BaCl 2 = Ba 2+ + 2Cl - Therefore, it is necessary to prove the presence of cations in the solution...... using qualitative reactions. and anions......
2 . According to table 2 ( Annex 1) select appropriate reagents The reagent for barium cations is ...... - anion, ...... The reagent for chloride - anions are cations......		1 . Cl - (chloride anions)
3 . To carry out the reaction, pour two samples of the original solution, each 0.5 ml in volume, into two test tubes 4. Add to the first test tube a colorless transparent solution of sulfuric acid......containing sulfate anions BaCl 2 + H 2 SO 4 = BaSO 4 + 2HCl Ba 2+ + 2Cl - + 2H + + SO 4 2- = BaSO 4 + 2H + + 2Cl - Ba 2+ + SO 4 2- = BaSO 4 Checking equations by sum of coefficients: in the molecular equation...... in the complete ionic equation…… in the reduced ionic equation……		2 . sulfate -, SO 4 2- silver, Ag+
5 . Add silver nitrate solution......containing silver cations to the second test tube A…… precipitate is formed as a result of the reaction BaCl 2 + 2AgNO 3 = Ba(NO 3) 2 + 2AgCl Ba 2+ + 2Cl - + 2Ag + + 2NO 3 - = Ba 2+ + 2NO 3 - + 2AgCl Ag + + Cl - = AgCl Sum of odds: in the molecular equation...... in the complete ionic equation…… in the reduced ionic equation……		4 .
Conclusion Using precipitation reactions, we proved that the barium chloride solution contains cations ...... and anions ......, thereby confirming the composition of the given salt		5 . white curd
Experience 2 Confirm the quality composition of iron (II) sulfate FeSO 4 = Fe 2+ + SO 4 2- Therefore, it is necessary, using qualitative reactions, to prove the presence of cations...... and anions...... in the solution.
2 . According to tables 2 and 3 ( Annex 1) select appropriate reagents The reagent for doubly charged iron cations is an alkali solution containing ...... - anions or a solution of red blood salt ...... The reagent for sulfate anions is barium cations......		1 . SO 4 2-, sulfate anions
3 . To carry out the reaction, pour three samples of the original solution, each 0.5 ml in volume, into three test tubes 4. Add sodium hydroxide solution to the first test tube A precipitate……color is formed as a result of the reaction FeSO 4 + 2NaOH = Na 2 SO 4 + Fe(OH) 2 Fe 2+ + SO 4 2- + 2Na + + 2OH - = 2Na + + SO 4 2- + …… Fe 2+ + 2OH - = ……		2 . OH - , hydroxide –
5 . Add a solution of red blood salt K 3 to the second test tube A precipitate……color is formed as a result of the reaction 3FeSO 4 + 2K 3 = 3K 2 SO 4 + Fe 3 2 3Fe 2+ + 3SO 4 2- + 6K + + 2 2- = 6K + + 3SO 4 2- + Fe 3 2 3Fe 2+ + 2 2- = Fe 3 2 The sums of the coefficients in the above equations are respectively equal to ……, ……, …… (When performing control work, only one qualitative reaction is carried out for the ion being determined)		4 . greenish
6 . Add barium chloride solution to the third test tube...... A precipitate……color is formed as a result of the reaction FeSO 4 + BaCl 2 = BaSO 4 + FeCl 2 Fe 2+ + SO 4 2- + Ba 2+ + 2Cl - = BaSO 4 + Fe 2+ + 2Cl - …… + …… = …… The sums of the coefficients in the given equations are respectively ……, ……, ……		5 .
Conclusion Using precipitation reactions, we proved that iron (II) sulfate contains a cation ...... and an anion ......		6 . Ba 2+ + SO 4 2- = BaSO 4 v
Experience 3 Confirm the quality composition of sodium carbonate 1. In an aqueous solution, this salt dissociates into ions Na 2 CO 3 = …… + …… Therefore, it is necessary, using qualitative reactions, to prove the presence of cations ...... and CO 3 2- (...... - anions) in the solution
2 . According to tables 1 and 2 ( Annex 1) select the appropriate qualitative reactions Sodium is determined by the color of the colorless flame of a gas burner (no experiment is carried out during the work). The reagent for carbonate anions is cations...... and acid solutions containing cations......		1 . Na + and (carbonate anions)
3 . To carry out qualitative reactions to carbonate ions, pour into two test tubes samples of the initial solution with a volume of 0.5 ml each 4. Add to the first test tube a solution of calcium chloride...... (or calcium hydroxide......) containing cations...... A white precipitate is formed, which dissolves when hydrochloric acid is added...... (at the same time, bubbles of transparent colorless gas appear in the test tube) When a precipitate forms, a reaction occurs Na 2 CO 3 + CaCl 2 = 2NaCl + CaCO 3 2Na + + CO 3 2- + Ca 2+ + 2Cl - = 2Na + + 2Cl - + CaCO 3 …… + …… = …… The sum of the coefficients in the equations is respectively ……, ……, …….		2 .
5 . Add hydrochloric acid solution to the second test tube...... An odorless gas is released, causing limewater to become cloudy (evidence of CO2 evolution: moisten glass with calcium hydroxide solution and hold over test tube until cloudy) Na 2 CO 3 + 2HCl = 2NaCl + CO 2 + H 2 O 2Na + + CO 3 2- + 2H + + 2Cl - = 2Na + + 2Cl - +CO 2 + H 2 O 2H + + CO 3 2- = CO 2 + H 2 O Sums of coefficients ……, ……, ……		4 . CaCl 2 or Ca(OH) 2 Ca 2+ (calcium) Ca 2+ + CO 3 2- = CaCO 3 v
Conclusion Using precipitation reactions and gas evolution reactions, we have proven that sodium carbonate solution contains …… – anions CO 3 2-		5.
Experience 4.(Substance recognition task) Using characteristic reactions, recognize the solutions of sulfuric acid, calcium hydroxide and calcium chloride contained in three numbered bottles (To recognize means to determine experimentally what substance is in each bottle) 1. Substances found in the solutions provided belong respectively to the classes ......, ....... and ......, and are (strong / weak) ...... electrolytes In an aqueous solution, these substances dissociate into ions H 2 SO 4 = 2H + + SO 4 2- Ca(OH) 2 = Ca 2+ + 2OH - CaCl 2 = Ca 2+ + 2Cl - Therefore, it is necessary, using qualitative reactions, to prove the presence of the following cations in the solution: H +, Ca 2+, and anions: SO 4 2-, OH -, Cl -
2 . According to tables 2 and 3 ( Annex 1) select the appropriate reagents Determined ion: Reagent: hydrogen cation H+…… calcium cation Ca 2+…… hydroxide - anion OH - …… sulfate - anion SO 4 2- …… chloride - anion Cl - ……		1 . base - (alkali) strong
3 . To carry out the reactions, pour 0.5 ml of each of the three samples into three clean test tubes Using the solubility table, select the sequence of adding reagents so that in one experiment you can form a precipitate in only one test tube: 5…… (may have no experience)		2 . CO 3 2-, Na 2 CO 3 litmus or phenolphthalein
4 . Add reagent #1 to three sample tubes. Record your observations in worksheet 2 5. Add reagent #2 to three new sample tubes. Write down your observations in table 2. If using reagents 1 and 2 you have established the qualitative composition of one of the samples, you can write it down in the corresponding line at the bottom of the table. No further experiments are carried out with this sample. 6. Add Reagent #3 to the remaining samples. Record your observations By analogy, continue working with reagents No. 4 and No. 5		3 . 1 or 2 - BaCl 2 2 or 1 - litmus test 3, 4, 5 - your options
7 . Fill out tables 2 and 3 and submit for verification

Homework. In addition to the abbreviated ionic equations of experiment 4 worksheet, write molecular and full ionic equations in your notebook.

table 2

Results of solving the recognition task

Table 3

Report on the performance of the recognition task (experiment 4)

Lesson - Practical work No. 4 (grade 9)

Lesson type: lesson- practiceusing information and communication technologies.

Topic: Solution experimental tasks on the topic: “Oxygen subgroup”.

Lesson objectives:

I . formation of UUD

1. Personal UUD - the possibility of self-determination in practical work based on intellectual capabilities (the organizer takes a sheet, assessing his abilities and capabilities).

2. Regulatory management control – goal formation, planning and organization of activities, forecasting, control, correction, evaluation.

3. Cognitive UUD - research actions (application of knowledge in a specific situation, solving experimental problems, as a component of developing logical thinking)

4 Communicative UUD – organizing and planning work in a group, the ability to negotiate and find a common solution, building interpersonal relationships.

II. Using knowledge about qualitative reactions to ions, learn to recognize chemical substances experimentally;

III. To develop the cognitive activity of students in the process of performing the experiment;

IV. Cultivate accuracy and careful attitude when using chemical reagents;

V. Strengthen skills in working with a virtual laboratory.

During the classes

Org moment.

Hello guys. Today we have guests at our lesson; these are chemistry teachers from schools in our region. Turn around and greet them. Amazing. Have a seat. I hope everyone has prepared notebooks, pens, and pencils for the lesson. Then let's begin.

Motivation:: add a word to a phrase

CHEMICAL

Pay attention to the board. I wrote only one word “CHEMICAL”, add words to make phrases (EXPERIMENTS, REACTIONS, PHENOMENA, PROCESSES, etc.)

Tell me, is there anything that can unite all these phrases? (Practical work).

Right. And today in class we will do practical work. We work, as usual, in groups. Open your notebooks, write down the date and topic of the work “Solving experimental problems on the topic “Oxygen subgroup”.

At home, you were preparing for today's lesson, looked at the problems on pages 146-147 of your textbooks and thought about the goal. How do you think it should sound?

apply the knowledge gained from studying the topic “Oxygen subgroup” in experimental problem solving;

strengthen the skills of conducting a chemical experiment.

Okay, let's write down the purpose of the work in your notebook.

What is necessary for the work to be successful and without health consequences?

Comply with safety regulations and rules for working in groups.

We repeat the rules of T.B. (we repeat according to the table, where only pictures are left)

RULES FOR WORK IN GROUPS:

Compliance with all safety regulations

Keep quiet, don't disturb others, they work too

Speak your thoughts, do not criticize others

Know how to negotiate and find a common solution.

On the tables there is a folder with instructions for performing the work. (20 minutes)

Distributing roles

A) organizer (works with the instruction card, finds out what to do, gives instructions to the performer)

B) performer - practitioner (carries out reactions)

B) controller-analyst (analyzes observations and corrects the work of the organizer)

We will solve the first problem (task No. 4 on page 147) with the help of a virtual laboratory. I invite one person from each group here. Guys, quickly assign roles. Have you decided? Begin. I remind the guys in the groups about drawing up a reporting table.

Thank you. You can sit down and continue working in your groups, but in different roles.

Conclusion : What conclusion did you draw based on the results of your work? Let's correct it.

Guys, our lesson is coming to an end. What can you say about today's work?

- I was most successful......

- I can praise myself for......

- I can praise my classmates.....

- I was surprised......

- In my opinion, it was not possible….., because…….

-For the future I will take into account……….

Okay, now

Everyone takes trays and notebooks to the teacher’s demonstration table and tidies up the workplace

Final part.

Thanks everyone for your work,You will learn the results in the next lesson. At home, repeat the composition of the air and think about the next task.

HOME EXPERIENCE

From the suggested materials: 50 ml., 9% acetic acid, 1 tbsp.NaHCO 3 (c ode), 100ml. H 2 O, 1 tbsp. a spoonful of detergent, beet juice, salt dough or plasticine. offer instructions for conducting a chemical experiment, which can serve as a visual aid in a geography lesson in 6th grade